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PubMed1991

Who enrolls in prevention trials? Discordance in perception of risk by professionals and participants.

Internal and external validity problems permeate all intervention studies but are accentuated in primary preventive intervention research, particularly when studies target or recruit individuals based on their risk for psychopathology. Since many people who are at risk do not yet experience distress, they may not perceive the need for intervention. Recruitment tactics based on explaining extent of risk are unlikely to be persuasive and may have negative consequences. If respondents are not motivated to participate, a small or biased subset of the target population will participate in the intervention. Bias is of special concern when those enrolled represent only part of the continuum of risk. Selective enrollment may compromise both internal validity (the interpretation of the research results) and external validity (the generalizability of the findings) of intervention trials in primary prevention. This article discusses the effects of partial enrollment and the resultant bias. It suggests several strategies for increasing the enrollment of the target population and examines some of their ethical ramifications. It also stresses the importance of collecting systematic data documenting how the participants in the intervention differ from the target group as a whole.

Bias↗

PubMed2001

Development of a patient-orientated instrument to measure service quality in outpatient departments.

AIMS OF THE STUDY: To describe three stages in the development of an instrument to measure service quality from the patients' perspective in hospital outpatient departments. RATIONALE: A reliable and valid service quality instrument is a valuable tool for collecting feedback from patients when improving outpatient services. DESIGN: A multiphase process with several versions of the questionnaire testing its validity and reliability. The first version of the questionnaire was constructed from information collected in a previous interview study of patients' service experiences. Using this version (47 questions) information was collected in 15 outpatient departments (314 patients) and the second version of the questionnaire was developed. At this stage, a survey of employees (n=111) was included in the development process. This second version of the questionnaire (43 questions) was used to collect more data in three outpatient departments of a university hospital and in two outpatient departments of two regional hospitals on three different occasions (1416, 369 and 124 patients) within a period of 2 years. The reliability of the instrument was tested in terms of stability by using three repeated measurements, and using the Cronbach's alpha coefficient as an indicator of internal consistency. Content validity was assessed by means of percentage agreement between staff and patients. Logistic regression analysis was performed to assess construct validity. RESULTS: The final version of the questionnaire contained 12 items. Agreement between patient and staff ratings was found to be acceptable for most questions (content validity). Two measurements on different occasions yielded a similar structure (construct validity). Internal consistency was acceptable (Cronbach's alpha = 0.67-0.93 in the first and 0.71-0.94 in the second survey). The variance of the alpha coefficients was small in the retest (stability). CONCLUSIONS: The instrument developed is general to the extent that it is suitable for assessing service quality improvement needs in individual units and for making cross-departmental comparisons.

Adult↗

PubMed1997

Maxillary sinusitis in adults: an evaluation of placebo-controlled double-blind trials.

BACKGROUND: In general practice, acute sinusitis is frequently diagnosed and treated with antibiotics. OBJECTIVE: This study aimed to determine the evidence for the effectiveness of antibiotic treatment in acute maxillary sinusitis in adults by assessing the methodological quality of placebo-controlled double-blind randomized trials. METHOD: An evaluation by four raters through a 35-item scoring-scale for internal and external validity of all placebo-controlled double-blind randomized trials on acute sinusitis found between January 1966 and July 1996. RESULTS: Eighty-five trials were excluded because they were not placebo-controlled, double-blind, randomized, or were carried out in patients with chronic sinusitis or in children. The three remaining trials were performed in different populations (one in general practice) between 1973 and 1978. Only one study claimed superiority of antibiotic treatment. Different inclusion criteria and major outcome measures were used by the authors. The reliability of major outcome events was reported poorly or not at all and in two studies outcome measures were clinically inappropriate. The studies scored 30-62% of the maximum attainable score for internal validity and 10-20% for external validity. CONCLUSION: The effectiveness of antibiotic treatment in acute maxillary sinusitis in a general practice population is not based sufficiently on evidence.

Acute Disease↗

PubMedDate not supplied

Worksite health and safety climate: scale development and effects of a health promotion intervention.

BACKGROUND: Environmental influences on health and health behavior have an important place in research on worksite health promotion. We tested the validity and internal consistency of a new measure of organizational health and safety climate that was used in a large randomized trial of a worksite cancer prevention program (the Working Well Trial). The resulting scales then were applied to assess intervention effects. METHODS: This study uses data from a subset of 40 worksites in the Working Well Trial. Employees at 20 natural gas pipeline worksite and 20 rural electrical cooperatives completed a cross-sectional questionnaire at baseline and 3-year follow-up. RESULTS: A factor analysis of this self-report instrument produced a two-factor solution. The resulting health and safety climate scales had good internal consistency (Cronbach's alpha = 0.74 and 0.82, respectively) and concurrent validity. The health climate scale was correlated more highly with organizational measures that were indicative of a supportive health climate than those indicating supportive safety climate, while the reverse was true of the safety climate scale. Changes in health climate were associated with the number of smoking and smokeless tobacco programs offered at the worksites at the time of the 3-year follow-up (r = 0.46 and 0.42, respectively). The scales were not correlated with most employee health behaviors. The health climate scores increased at intervention worksites, compared with scores at control worksites (F[1,36] = 7.57, P = 0.009). CONCLUSIONS: The health and safety climate scales developed for this study provide useful instruments for measuring organizational change related to worksite health promotion activities. The Working Well Intervention resulted in a significant improvement in worksite health climate.

Cross-Sectional Studies↗

PubMed1993

Establishing the reliability and validity of a new instrument: pilot testing.

Development of instruments to measure psychosocial variables is a complex process that begins with concept analysis and concludes with pilot testing to establish initial reliability and validity properties. Although the instrument development process is lengthy. PACU nurses are encouraged to follow all steps; if they do not, they will be unsure of what is measured or the meaning of the finding. Discussed here is the final phase of the instrument development process; calculating and analyzing construct validity and internal consistency reliability. An example is given that applies reliability and validity methods to a hypothetical instrument.

Factor Analysis, Statistical↗

PubMed2001

Clinical applications of wall-stress analysis in the pediatric intensive care unit.

OBJECTIVE: To determine whether serial, noninvasive assessment of afterload, contractility, and Doppler-derived cardiac output reliably detects variations in cardiac function in unstable pediatric patients. DESIGN: Prospective, blinded clinical trial. SETTING: The pediatric intensive care unit at Massachusetts General Hospital. PATIENTS: Fourteen critically ill pediatric patients. INTERVENTIONS: Pediatric patients meeting criteria for hemodynamic instability underwent serial echocardiograms every 6 hrs until they met exit criteria, generating 75 studies. MEASUREMENTS AND MAIN RESULTS: Shortening fraction, cardiac index (CI), end-systolic wall stress (ESWS), and corrected velocity of circumferential shortening (Vcfc) were measured in each patient. Data points were plotted as a stress-velocity relationship, compared with published normal values, then correlated with changes in vital signs and pharmacologic interventions. Fourteen of 16 patients who were enrolled completed the study. A strong negative correlation between ESWS and Vcfc was confirmed (p < .001). As an internal measure of validity, Vcfc had a strong positive correlation with CI measurements (p = .012). An increase in dopamine infusion was associated with a fall in ESWS (p = .02), an increase in Vcfc (p = .03), and an increase in the CI as measured by Doppler (p = .035). The infusion of dopamine above renal perfusion levels moved patients from zones of normal or compensated contractility for afterload on a modified stress-velocity relationship to a zone of high contractility for afterload. Urine output was the only clinical index of cardiac function that had a significant correlation with the echocardiographic indices. Hemodynamically unstable patients followed similar patterns of deterioration and recovery on the modified stress-velocity graph. All surviving patients returned to a normal or compensated zone. CONCLUSIONS: Wall-stress analysis of cardiac function is easily and safely performed on mechanically ventilated pediatric patients with the production of consistently high-quality data. For internal validity, Vcfc and CI measurements were correlated and were strongly positive. Wall-stress indices reliably detected patient deterioration, recovery, and response to changes in dopamine infusion. Patients who failed to return to areas of normal or compensated levels of contractility and afterload did poorly in this study. Noninvasive measures of afterload and contractility appear useful for monitoring cardiac function of critically ill children in an intensive care setting.

Adolescent↗

PubMed2003

Psychometric properties of the Rivermead Mobility Index in Italian stroke rehabilitation inpatients.

OBJECTIVE: To examine the internal consistency, validity, responsiveness and test scalability of the Rivermead Mobility Index (RMI) in Italian rehabilitation inpatients recovering from stroke. DESIGN: Seventy-three stroke inpatients undergoing rehabilitation were assessed at admission (T0) and five weeks later (T1), using RMI, the motor (motFIM) and cognitive (cognFIM) subscales of the Functional Independence Measure, the 'leg' section of the Motricity Index and Trunk Control Test. RESULTS: Cronbach's alpha of the RMI was 0.92. The item-to-total correlation coefficients (r(rb)) ranged from 0.36 to 0.83, all p < 0.003. All correlations between RMI scores and the other instruments, both at T0 and T1, were statistically significant (r > or = 0.49, all p < 0.0001), except those with cognFIM. The difference in RMI scores over the testing period was statistically significant (sign test: z = 7.1, p < 0.0001) and the effect size was 0.89. The coefficient of reproducibility was 0.95 at T0 and 0.93 at T1, and both coefficients of scalability were 0.67. CONCLUSIONS: The study confirms the internal consistency, construct validity and responsiveness of the RMI, according to the classic psychometric indexes. However, some minor concerns arise regarding: (a) a floor effect of RMI in subacute rehabilitation stroke inpatients at admission and; (b) one item ('bathing') that seems sensitive to cultural and environmental factors. Moreover, even though RMI met the scaling criteria, the item hierarchy is not coincident with the one originally postulated. So, RMI should be considered only as a summated index with ordinal properties, and not a hierarchically ranked scale.

Aged↗

PubMed2004

Determination of antibiotic substances in hospital sewage water using solid phase extraction and liquid chromatography/mass spectrometry and group analogue internal standards.

A method for determination of antibiotics in hospital sewage water has been developed and validated. Analogue internal standards for fluoroquinolones, sulfonamides, trimethoprim, beta-lactams (penicillins and cephalosporins), nitroimidazoles and tetracyclines were successfully used for calibration and shown to generally improve precision compared to external calibration. Matrix components caused ion suppression/enhancement effects during the MS detection for all analytes studied. Two effects were observed: general suppression and short-term variations in the MS response. In the hospital sewage water large temporal variations in the analyte concentration were observed during the course of the sampling period (seven grab samples in 13 h). Analyte concentrations varied within the following ranges (in microg l(-1)): ciprofloxacin, 3.6-101.0; metronidazole, 0.1-90.2; sulfamethoxazole, 0.4-12.8; ofloxacin, 0.2-7.6; trimethoprim, 0.6-7.6; and doxycycline, 0.6-6.7.

Anti-Bacterial Agents↗

PubMed2005

The French Aging Males' Symptoms (AMS) scale: methodological review.

BACKGROUND: The AMS is an internationally used health-related quality of life (HRQoL) scale. The aim of this paper is to provide evidence that the French AMS scale measures HRQoL are as valid as other language versions. We also intend to show whether the application of AMS is really limited to aging males only or not. More generally, we like to demonstrate that the AMS scale is a relevant, validated, sensitive instrument to measure HRQoL and change of symptoms in France. METHODS: We performed a representative survey in France to get data AMS scale data. The French data were compared with existing data from other European countries. Only community-based data were used for this comparison. RESULTS AND DISCUSSION: Reliability (here consistency, Cronbach' s alpha) was found to be good and almost identical with other countries. VALIDITY: the internal structure of the AMS (factorial analysis) was sufficiently comparable with the comparison group of other countries in Europe to conclude that the scale really measures the same phenomenon. The sub-scores and total score correlations (Pearson) were high (r = 0.8-0.9) but only somewhat lower among the sub-scales (r = 0.5-0.7). This suggests that the domains are correlated. The comparison of the French AMS with the generic quality-of-life scale SF-12 showed a good correlation (Pearson r = 0.48-0.51) as reported from other countries. We observed also a good correlation between the AMS scale and the depression scale HAD (Pearson r = 0.62). The analysis of the AMS structure across age groups showed sufficient similarity to suggest that the AMS is also useful for younger age groups. CONCLUSION: The French AMS scale is a standardized HRQoL scale with good psychometric characteristics (reliability, validity) as shown for other international versions. We suggest that the AMS scale could be also used in age groups under 40 years to measure and compare HRQoL in males. Since the application of the AMS in younger age was not investigated before, confirmation in future studies is needed.

Adolescent↗

PubMed1997

Internal consistency reliability and predictive validity of a modified N. Huang clinical scoring system in adult cystic fibrosis patients.

We described a modified N. Huang scoring system and its application as a measure of disease status and progression in a population of adult cystic fibrosis patients. We evaluated the scoring for internal consistency reliability and predictive validity. We applied the scoring system to 109 adult cystic fibrosis patients followed at the Montreal Chest Institute. Complete data were available on 36 deceased patients. The total score represented the sum of the clinical, radiological and pulmonary function subscores, minus the complications subscore. It ranged between 0 (worst health) and 100 points (best health). The total score showed a high degree of internal consistency and reliability with an estimated Cronbach coefficient alpha of 0.934. Both total score and forced expiratory volume in one second (FEV1) percentage predicted were significant predictors of survival at 36 and 24 months. However, there was a progressive decrease in the discriminating power of FEV1 percentage pred for predicting survival at 24, 18, 12 and 6 months. The total score showed a progressive and consistent pattern clearly predicting the outcome. A total score < 41, < 38, < 35 and < 30 points was associated with a poor prognosis for survival at 24, 18, 12, and 6 months, respectively. The clinical and complications subscores were the most discriminating components of the total score. The total score of the modified N. Huang scoring system offered a better discriminating scale, as compared to forced expiratory volume in one second % predicted, in the prognostic evaluation of end-stage cystic fibrosis patients. It could be of value in decisions for lung transplantation in these patients.

Adolescent↗

PubMed2003

The reliability and validity of the American Board of Internal Medicine Monthly Evaluation Form.

PURPOSE: To report indicators of reliability and validity of the American Board of Internal Medicine Evaluation Form (ABIM-MEF) at one institution (Wright-Patterson Medical Center). METHOD: Completed ABIM-MEFs from 1990-1999 were reviewed. Reliability measures included Cronbach alpha, interrater reliability, and rating consistency between different types of staff and rotations. Construct validity was investigated by tracking ABIM-MEF scores over time and with factor analysis. Predictive validity was assessed by correlating ABIM-MEF scores with the In-training Examination and ABIM Certifying Examination results RESULTS: The 71 residents averaged 12 ABIM-MEFs per year. The forms had a Cronbach alpha of 0.96 and high interrater reliability (intraclass correlation coefficients > 0.80). Ratings did not differ by type of attending or rotation, except that noninternists rated residents lower on procedural skills. ABIM-MEF questions about judgment, knowledge, and clinical skills showed significant improvement from month to month during each academic year as well as year to year. In contrast, questions on professional attitudes, humanism, and procedural skills sections improved between postgraduate year 1 and postgraduate year 2 only. ABIM-MEF questions collapsed into two domains in factor analysis: judgment-knowledge-skills and attitude-humanism. ABIM-MEF questions from judgment and knowledge sections modestly predicted In-training Examination and ABIM Certifying Examination results. In contrast, professional attitude, humanism, and clinical as well as procedural skill questions had little discriminative ability. CONCLUSIONS: The ABIM-MEF appears to be reliable and valid. Further, factor analysis results support the ABIM's movement to simplify the monthly evaluation form to the new Accreditation Council for Graduate Medical Education core competencies.

Academic Medical Centers↗

PubMed2005

Test-retest reliability, internal item consistency, and concurrent validity of the wheelchair seating discomfort assessment tool.

Discomfort is a common problem for wheelchair users. Few researchers have investigated discomfort among wheelchair users or potential solutions for this problem. One of the impediments to quantitative research on wheelchair seating discomfort has been the lack of a reliable method for quantifying seat discomfort. The purpose of this study was to establish the test-retest reliability, internal item consistency, and concurrent validity of a newly developed Wheelchair Seating Discomfort Assessment Tool (WcS-DAT). Thirty full-time, active wheelchair users with intact sensation were asked to use this and other tools in order to rate their levels of discomfort in a test-retest reliability study format. Data from these measures were analyzed in SPSS using an intraclass correlation coefficient (ICC) model (2,k) to measure the test-retest reliability. Cronbach's alpha was used to examine the internal consistency of the items within the WcS-DAT. Concurrent validity with similar measures was analyzed using Pearson product-moment correlations. ICC scores for all analyses were above the established lower bound of .80, indicating a highly stable and reliable tool. In addition, alpha scores indicated good consistency of all items without redundancy. Finally, correlations with similar tools, such as the Chair Evaluation Checklist and the Short Form of the McGill Pain Questionnaire, were significant at the .05 level, and many were significant at the .001 level. These results support the use of the WcS-DAT as a reliable and stable tool for quantifying wheelchair seating discomfort. Its application will enhance the ability to assess and to research this important problem and will provide a means to validate the outcomes of specialized seating interventions for the study population of wheelchairs users.

Persons with Disabilities↗

PubMed2006

Development and validation of the self-administration of medication tool.

BACKGROUND: Consumer participation in planning and implementing health care is actively encouraged as a means of improving patient outcomes. In assessing the ability of patients to self-medicate, health professionals can identify areas in which patients need assistance, education, and intervention to optimize their health outcomes after discharge. OBJECTIVE: To develop and validate a tool to quantify the ability of patients to administer their regularly scheduled medications while they are hospitalized. METHODS: Past research enabled us to develop the Self-Administration of Medication (SAM) tool. Using a Delphi technique of 3 rounds, a panel of expert health professionals established the content validity of the tool. For determining level of agreement in using the SAM tool, 56 patients were selected; for each patient, 2 randomly selected nurses completed an assessment. Construct validity and internal consistency were examined by testing the tool in 50 patients and comparing with other validated scales. RESULTS: The 29-item SAM tool had high content validity scores for clarity, representation, and comprehensiveness, with content validity index values ranging from 0.95-1.0. In testing the level of agreement between 2 nurses, out of 43 valid cases, 95.3% of nurses overwhelmingly agreed about the patients' competence to self-administer their drugs. The intraclass correlation coefficient was 0.819 (95% CI 0.666 to 0.902). Internal consistency for the SAM tool was high, with a Cronbach's alpha of 0.899. A moderate to strong correlation was obtained when comparing the SAM tool with other validated measures. CONCLUSIONS: The SAM tool is valid and reliable for quantifying patients' ability to manage their regularly scheduled medications in the hospital setting.

Adult↗

PubMed1994

Reliability, validity and factor structure of the 12-item General Health Questionnaire among young males in Italy.

The internal consistency, validity and factor structure of the 12-item General Health Questionnaire (GHQ-12) were investigated in a homogeneous sample consisting of 18-year-old males in Italy. The GHQ-12 proved to be a reliable instrument, as indicated by a Cronbach's alpha of 0.81. When the screening characteristics of the GHQ-12 (scored by the Likert method) were evaluated against the psychiatrist's ratings, the best balance between sensitivity and specificity was found at the GHQ cut-off score of 8/9: at this threshold, sensitivity was 0.68 and was paired to a specificity of 0.59 and an overall misclassification rate of 0.40. Validity coefficients based on a single severity score were rather low compared with those reported in other settings. When a principal components analysis with varimax (and oblimin) rotation was performed, two factors were identified: factor A (general dysphoria) was defined by 7 items related to anxiety and depression; factor B (social dysfunction) included 6 items testing the ability to perform daily activities and to cope with everyday problems. The identified factors revealed distinct ability in the discrimination between subjects with and without emotional disturbance according to the psychiatrist's ratings and correlated differently with 3 Minnesota Multiphasic Personality Inventory subscales (depression, D; conversion hysteria, Hy; psychasthenia, Pt). Thus, the factor structure of the GHQ-12 might provide useful information along with that offered by a single severity score, and the detection of cases might be improved by examining an individual's profile of scores on different subscales derived from factor analysis.

Activities of Daily Living↗

PubMed1993

Subjective assessment of nutritional status-validity and reliability of a modified Detsky index in a Swedish setting.

In the search for a clinically useful nutritional index for use in a European context, we have translated an American nutritional assessment index - Subjective Global Assessment (SGA), and tested the modified translated version for validity and reliability in a Swedish setting. Judgements by an expert panel resulted in a mean agreement of 71% for clarity, 80% for content validity and 65% for internal consistency. Construct validity was demonstrated by the use of contrasting patient-groups (n = 20) and by 90% agreement with a medical expert as 'gold standard' for unknown patients (n = 20). Inter-rater reliability showed 75% agreement by 3 Registered Nurses (RNs) (n = 20). The individual Kappas for the raters varied from 0.68 to 0.89. The study showed difficulties experienced by raters in relating certain aspects in the SGA-index to normality. However, we concluded that a modified SGA-index translated from one language to another, with all the problems of cultural and idiomatic differences, can be of value for assessing and documenting pre-operative nutritional status of patients undergoing gastrointestinal surgery in a Swedish setting.

Journal Article↗

PubMed2005

LC determination of glimepiride and its related impurities.

Five impurities in glimepiride drug substance were detected and quantified using a simple isocratic reverse phase HPLC method. For the identification and characterization purpose these impurities were isolated from a crude reaction mixture of glimepiride using a normal phase HPLC system. Based on the spectroscopic data like NMR, FTIR, UV and MS these impurities were characterized and used as impurity standards for determining the relative response factor during the validation of the proposed isocratic reverse phase HPLC method. The chromatographic separation was achieved on a Phenomenex Luna C8 (2) 100 A, 5 microm, 250 mm x 4.6 mm using a mobile phase consisting of phosphate buffer (pH 7.0)-acetonitrile-tetrahydrofuran (73:18:09, v/v/v) with UV detection at 228 nm and a flow rate of 1 ml/min. The column temperature was maintained at 35 degrees C through out the analysis. The method has been validated as per international guidelines on method validation and can be used for the routine quality control analysis of glimepiride as active pharmaceutical ingredient (API).

Chromatography, High Pressure Liquid↗

PubMed2004

Standardised evaluation of the performance of a simple membrane filtration-elution method to concentrate bacteriophages from drinking water.

The bacteriophage elution procedure described further after adsorption to acetate-nitrate cellulose membrane filters allows better recovery of phages concentrated from 1l of water than elution procedures used previously. The improvement is due to the combined effect of the eluent (3% (w/v) beef extract, 3% (v/v) Tween 80, 0.5M NaCl, pH 9.0) and the application of ultrasound instead of agitation or swirling. Average recovery of somatic coliphages, 82 +/- 7%, was the greatest, and that of phages infecting Bacteroides fragilis, 56 +/- 8%, the lowest, with intermediate values for F-specific and F-specific RNA bacteriophages. Thus, the method allowed recovery of over 56% for all the phages suggested as surrogate indicators. The method was then validated according to an International Standardisation Organisation validation standard procedure and implemented in routine laboratories, which obtained reproducible results.

Bacteriophages↗

PubMedDate not supplied

Validating the Alcohol Use Disorder Identification Test with college first-offenders.

Although the Alcohol Use Disorders Identification Test (AUDIT) has been shown to have good validity and reliability with clinical samples, little data has been examined with respect to youthful problem drinkers, particularly college students. Data collected with 312 students cited their first time for breaking university drinking rules was examined to evaluate the factorial validity and internal consistency of the 10-item scale, and also to test the validity of the AUDIT against two scales designed with a previous cohort specifically to measure hazardous (The Drinking Context Scale) and harmful drinking (the College Alcohol Problem Scale) in college students. Overall, results suggest that the AUDIT is a valid and reliable screening device for college students, and could play an important role in assessing youthful problem drinkers for early intervention programming.

Adolescent↗